#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Date    : 2018-05-22 22:36:27
# @Author  : Chen Jing (cjvaely@foxmail.com)
# @Link    : https://github.com/Cjvaely
# @Version : $Id$

# generator
# 把杨辉三角每一行看做一个list，
# 试写一个generator，不断输出下一行的list：


def triangles():
    L = [1]
    while True:
        yield L
        L.append(0)
        L = [L[i - 1] + L[i] for i in range(len(L))]

# 期待输出:
# [1]
# [1, 1]
# [1, 2, 1]
# [1, 3, 3, 1]
# [1, 4, 6, 4, 1]
# [1, 5, 10, 10, 5, 1]
# [1, 6, 15, 20, 15, 6, 1]
# [1, 7, 21, 35, 35, 21, 7, 1]
# [1, 8, 28, 56, 70, 56, 28, 8, 1]
# [1, 9, 36, 84, 126, 126, 84, 36, 9, 1]


n = 0
results = []
for t in triangles():
    # print('print t----------------------------------')
    print(t)
    results.append(t[:])
    # print('print results----------------------------------')
    # print(results)
    n = n + 1
    if n == 10:
        break
# print(results)  # 测试results
if results == [
    [1],
    [1, 1],
    [1, 2, 1],
    [1, 3, 3, 1],
    [1, 4, 6, 4, 1],
    [1, 5, 10, 10, 5, 1],
    [1, 6, 15, 20, 15, 6, 1],
    [1, 7, 21, 35, 35, 21, 7, 1],
    [1, 8, 28, 56, 70, 56, 28, 8, 1],
    [1, 9, 36, 84, 126, 126, 84, 36, 9, 1]
]:
    print('测试通过!')
else:
    print('测试失败!')
